Lactobacillus acidophilus
is a "friendly" strain of bacteria used to make yogurt and cheese. Although we are born without it, acidophilus soon establishes itself in our intestines and helps prevent intestinal infections. Acidophilus also flourishes in the vagina, where it protects women against yeast infections.

Acidophilus is one of several microbes known collectively as
probiotics
(literally, "pro life," indicating that they are bacteria and yeasts that help rather than harm). Others include the bacteria
L. bulgaricus
,
L. reuteri
,
L. plantarum
,
L. casei
,
B. bifidus
,
S. salivarius
,
and
S. thermophilus
and the yeast
Saccharomyces boulardii
.
Your digestive tract is like a rain forest ecosystem with billions of bacteria and yeasts rather than trees, frogs, and leopards. Some of these internal inhabitants are more helpful to your body than others. Acidophilus and related probiotics not only help the digestive tract function, they also reduce the presence of less healthful organisms by competing with them for the limited space available. For this reason, use of probiotics can help prevent infectious diarrhea.

Antibiotics can disturb the balance of your "inner rain forest" by killing friendly bacteria. When this happens, harmful bacteria and yeasts can move in and flourish. This can lead to vaginal yeast infections. Conversely, it appears that the regular use of probiotics can help prevent vaginal infections and generally improve the health of the gastrointestinal system. Whenever you take antibiotics, you should probably take probiotics as well and continue them for some time after you are done with the course of treatment.

Sources

Although we believe that they are helpful and perhaps even necessary for human health, we don't have a daily requirement for probiotic bacteria. They are living creatures, not chemicals, so they can sustain themselves in your body unless something comes along to damage them, such as antibiotics.

Cultured dairy products, such as yogurt and kefir, are good sources of acidophilus and other probiotic bacteria. Supplements are widely available in powder, liquid, capsule, or tablet form. Grocery stores and natural food stores both carry milk that contains live acidophilus. In addition to probiotics, related substances known as
prebiotics
may enhance the colonization of healthy bacteria in the intestinal tract.
140

Therapeutic Dosages

Dosages of acidophilus are expressed not in grams or milligrams, but in billions of organisms. A typical daily dose should supply about 3 to 5 billion live organisms. Other probiotic bacteria are used similarly. The typical dose of
S. boulardii
yeast is 500 mg twice daily (standardized to provide 3 x 10
10
-colony-forming units per gram), to be taken while traveling or at the start of using antibiotics, and continued for a few days after antibiotics are stopped.

Because probiotics are not drugs, but rather living organisms that you are trying to transplant to your digestive tract, it is necessary to take the treatment regularly. Each time you do, you reinforce the beneficial bacterial colonies in your body, which may gradually push out harmful bacteria and yeasts growing there.

The downside of using a living organism is that probiotics may die on the shelf. In fact, a study reported in 1990 found that most acidophilus capsules on the market contained no living acidophilus.
1
The situation has improved in subsequent evaluations, but still some products are substandard.
99
The container label should guarantee living organisms at the time of purchase, not just at the time of manufacture. Another approach is to eat acidophilus-rich foods such as yogurt, in which the bacteria are most likely still alive.

To treat or prevent vaginal infections, mix 2 tablespoons of yogurt or the contents of a couple of capsules of acidophilus with warm water and use as a douche.

Finally, in addition to increasing your intake of probiotics, you can take fructo-oligosaccharides,
supplements that can promote thriving colonies of helpful bacteria in the digestive tract. (Fructo-oligosaccharides are carbohydrates found in fruit.
Fructo
means "fruit," and an
oligosaccharide
is a type of carbohydrate.) Taking this supplement is like putting manure in a garden; it is thought to foster a healthy environment for the bacteria you want to have inside you. The typical daily dose of fructo-oligosaccharides is between 2 g and 8 g.

Probiotics may be helpful for controlling symptoms and maintaining remission in
ulcerative colitis
.
37-39,82,204,222
However, probiotics may be less useful for
inducing
remission; when probiotics were added to standard medications used for induction of remission, no additional benefits were seen in a study of people with mild-to-moderate ulcerative colitis.
155

Probiotics might help prevent
colds
,
43
possibly by
improving immunity
.
40-42,83,164
On a related note, one small, double-blind study found evidence that use of the probiotic bacteria
Lactobacillus fermentum
improved the effectiveness of the influenza vaccine.
135
(The probiotic supplement was taken in two doses. One was taken two weeks before the vaccine, and the other was taken two weeks after.)

The bacteria
Gardnerella vaginalis
can cause a different type of
vaginal infections
; as with vaginal yeast infections, probiotics have shown some promise for this condition, but evidence remains inconclusive.
145,158,175,190
A trial of 64 women taking a single dose of tinidazole for bacterial vaginosis suggests that women who also took daily probiotics capsules had better cure rates at 4 weeks.
195
A larger trial involving 120 women with a history of bacterial vagninosis found that taking one capsule daily of the probiotics
Lactobacillus rhamnosus
, acidophilus, and
Streptococcus thermophilus
reduced recurrence.
209

The bacteria
Helicobacter pylori
is the main cause of
ulcers
in the stomach and duodenum. Antibiotics can kill
H. pylori
, but more than one must be used at the same time, and, even then, the bacteria is not necessarily eradicated. Probiotics may be helpful.
Evidence suggests that various probiotics can inhibit the growth of
H. pylori
.
65-67,87,169
While this effect does not appear to be strong enough for probiotic treatment to eradicate
H. pylori
on its own, preliminary evidence, including several small double-blind trials, suggest that various probiotics may help standard antibiotic therapy work better, reducing side effects and possibly increasing rate of eradication.
47,55,58,60,63,65,67,87,88, 97,98,131,148,149,162,185
For example, over a 2-week period, 82 adults with dyspepsia and
H. pylori
infection were randomized to receive lansoprazole (30 mg), amoxicillin (1,000 mg), clarithromycin (500 mg), plus kefir (a cultured dairy product rich in probiotics) or the medications plus placebo. Those in the kefir group experienced a better rate of
H. pylori
eradication and an improvement in their symptoms (eg, diarrhea, nausea, abdominal pain) compared to the placebo group.
217

Various probiotics might be helpful for
allergic rhinitis
(hay fever).
102-103,142
While there is some evidence that probiotics can help reduce symptoms of milk allergies,
49
one study found that adding probiotics to infant cow’s milk formula was not helpful.
176
One interesting study found that the use of probiotics during pregnancy and breastfeeding may decrease the likelihood that a highly allergic mother will pass her allergic tendencies to her breastfed infant.
180

One double-blind, placebo-controlled study of 70 people with
chronic constipation
found some evidence of benefit with
Lactobacillus casei Shirota
.
89
Another study found that
Lactobacillus rhamnosus
was helpful for chronic constipation in children.
141
A small trial also found benefits in children, this time with a mixture of
bifidobacteria
and
lactobacilli
.
151
In another study, a combination of
B. lactis
and
B. longus
showed promise for improving bowel regularity in nursing home residents.
146
Finally, in a 6-week double-blind, placebo-controlled trial of 274 people with constipation-predominant irritable bowel syndrome, use of a probiotic formula containing
B. animalis
significantly improved stool frequency.
144

A preliminary double-blind, placebo-controlled study found evidence that
Lactobacillus GG
might potentially be helpful for treating antibiotic-resistant bacteria.
138
This small study followed 23 people with severe kidney disease who tested positive for vancomycin-resistant bacteria in the stool. (Vancomycin is one of the main “last-ditch” antibiotics for treatment of resistant bacteria.) Use of a yogurt product containing
L. rhamnosus
appeared to be more effective at ridding the gastrointestinal tract of these bacteria than placebo. However, the study suffered from a number of flaws, especially its small size. Note also that participants in this study did not have active infection with antibiotic-resistant bacteria; they were carriers for it. Do
not
attempt to use probiotics as sole treatment for active infection with resistant bacteria.

On a related note, preventive use of probiotics does not appear to help prevent the development of resistant bacterial strains that may arise during antibiotic treatment.
96,111

Probiotic treatment has also been proposed as a treatment for
canker sores
and as a preventative measure against colon
cancer
, but there is no solid evidence that it is effective.

Probiotics have shown some promise for helping to prevent
cavities
by antagonizing cavity-causing bacteria.
90

One study found that giving probiotics to certain critically ill people could help prevent multiple organ failure.
133

One small, placebo-controlled study found that use of
L. helveticus
might improve sleep quality in seniors, for reasons that are not at all clear.
152

An open study found hints that probiotics might be helpful for mouth sores caused by Behcet’s syndrome.
147

As noted above, probiotics have shown some promise in the treatment of infections with the yeast
Candida albicans
. Probiotics are also proposed for the treatment of a theoretically related, but markedly controversial condition, known as
yeast hypersensitivity syndrome
(also known as chronic candidiasis, chronic candida, systemic candidiasis, or just
candida
). As described by some alternative medicine practitioners, yeast hypersensitivity syndrome is a common problem that consists of a population explosion of the normally benign
candida
yeast that live in the vagina and elsewhere in the body, coupled with a type of allergic sensitivity to it. Probiotic supplements are widely recommended for this proposed condition because they establish large, healthy populations of friendly bacteria that compete with the
candida
that is trying to take up residence. However, there is no evidence that yeast hypersensitivity is a common problem, and virtually none that it exists at all.

In one small, 12-week study,
Lactobacillus GG
failed to prove more effective than placebo for the treatment of
rheumatoid arthritis
.
91

Evidence for the effectiveness of probiotics in preventing urinary tract infections has been mixed. A year-long open trial of 150 women, for example, failed to find
Lactobacillus
probiotics effective for preventing
urinary tract infections
as compared to
cranberry
juice or no treatment.
50
And a randomized trial involving 252 postmenopausal women found that Lactobacilli rhamnosus did not reduce the number of urinary tract infections compared to antibiotics.226 Other studies, however, including a large (453-participant), 3-month, double-blind, placebo-controlled study of a special healthy
E. coli
probiotic, did find benefits.107,175

A substantial study failed to find a mixture of
L. casei
,
L. bulgaricus
,
and
S. thermophilus
in yogurt and milk helpful for
asthma
in children.
142
But, another study found that the combination of a probiotic (
Bifidobacterium breve
) and a prebiotic (galacto/fructo-oligosaccharide) may help reduce wheezing in infants with eczema.
206

Probiotics have also been studied as possible treatment for
liver disease
. In one such study, 84 adults (aged 18-65) with liver disease (
cirrhosis
or
hepatitis
) were randomized to receive yogurt (1 cup, 3 times daily) with or without the probiotics
B. bifidus
,
L. acidophilus
,
L. bulgaricus
, and
S. thermophilus
.
212
After 2 weeks, the people in the probiotics group experienced an improvement in their symptoms (eg, improved food intake and appetite).
Chronic liver disease with cirrhosis can lead to a potentially life-threatening brain abnormality, called hepatic encephalopathy. A 2011 review of 7 randomized trials involving 550 people found inconclusive evidence to support the use of probiotics as a treatment for this condition.
218

What Is the Scientific Evidence for Acidophilus and Other Probiotics?

Traveler's Diarrhea

According to several studies, it appears that regular use of acidophilus and other probiotics can help prevent "traveler's diarrhea" (an illness caused by eating contaminated food, usually in developing countries).
4,12
One double-blind, placebo-controlled study followed 820 people traveling to southern Turkey, and found that use of
Lactobacillus GG
significantly protected against intestinal infection.
7

Other studies using
S. boulardii
have found similar benefits,
11,13,14
including a double-blind, placebo-controlled trial enrolling 3,000 Austrian travelers.
14
The greatest benefits were seen in travelers who visited North Africa and Turkey. The researchers noted that the benefit depended on consistent use of the product, and that a dosage of 1,000 mg daily was more effective than 250 mg daily.

Infectious Diarrhea

Probiotics may also help prevent or treat acute infectious diarrhea in children and adults.

A 2001 review found 13 double-blind, placebo-controlled trials on the use of probiotics for acute infectious diarrhea in infants and children; 10 of these trials involved treatment and 3 involved prevention.
71
Overall, the evidence suggests that probiotics can significantly reduce the duration of diarrhea and perhaps help prevent it. The evidence is strongest for the probiotic
Lactobacillus GG
and for infection with a particular virus called rotavirus, which causes severe diarrhea in children.

Another more recent review of 63 trials involving over 8,000 people (mainly infants and children) found that probiotics reduced how long the episode of diarrhea lasted.
210
However, the authors concluded that more research needs to be done to determine which probiotics work best for infectious diarrhea.

And, in a subsequent smaller review focusing on persistent diarrhea (lasting for 2 weeks or longer), researchers concluded that probiotics are capable of reducing both the duration of the diarrhea episode as well as the stool frequency.
211
Another study that was part of this same review suggested that probiotics may help to reduce how long a child is hospitalized due to diarrhea.

One double-blind, placebo-controlled trial of 269 children (ages 1 month to 3 years) with acute diarrhea found that those treated with
Lactobacillus GG
recovered more quickly than those given placebo.
22
The best results were seen among children with rotavirus infection. Similar results with
Lactobacillus GG
were seen in a double-blind study of 71 children.
59
However, 224 young Chinese children with severe, acute diarrhea found no benefit from lactose-free formula supplemented with
Bifidobacteria
and
S. thermophilus
, suggesting that probiotics may not be as useful for cases of severe, dehydrating diarrhea.
170
Also,
Lactobacillus rhamnosus
GG is not always associated with improvement. When given for 10 days to 229 infants from rural India hospitalized with acute diarrhea it did not reduce the severity of the diarrhea during that time period.
198

In addition, a double-blind study evaluated the possible benefits of the probiotic
L. reuteri
in 66 children with rotavirus diarrhea.
5
The study found that treatment shortened the duration of symptoms, and the higher the dose, the better the effect.
Similar benefits were seen in a placebo-controlled trial of 151 infants and children given the probiotic
Escherichia coli
Nissle 1917 (a safe strain of
E. coli
) for 21 days for nonspecific (presumably viral) cases of mild to moderate diarrhea.
181

A double-blind, placebo-controlled study of 81 hospitalized children found that treatment with
Lactobacillus GG
reduced the risk of developing diarrhea, particularly rotavirus infection.
61
A double-blind, placebo-controlled study found that
Lactobacillus GG
helped prevent diarrhea in 204 undernourished children.
62

Other studies, though not entirely consistent, generally indicate that the probiotics
B. bifidum
,
S. thermophilus, L. casei
,
Lactobacillus LB
,
and
S. boulardii
—both individually and combined with
L. reuteri
and
L. rhamnosus
—may also help prevent or treat diarrhea in infants and children.
8,9,11,15,23,26,56,57,92-93,108-109,150,183,220
One study found that bacteria in the
B. bifidum
family can kill numerous bacteria that cause diarrhea.
69

Researchers also studied whether adding
Lactobacillus fermentum
could have preventive benefits.
221
Two hundred and fifteen healthy infants were randomized to receive formula with prebiotics plus
L. fermentum
or the formula and prebiotics only. The infants in the
L. fermentum
group had fewer cases of gastrointestinal and upper respiratory infection.

Keep in mind that diarrhea in young children can be serious. If it persists for more than a day, consult a physician.

A large (211-participant), double-blind, placebo-controlled study found that adults with diarrhea can benefit from probiotic treatment as well.
26
Another study found that regular use of probiotics could help prevent gastrointestinal infections in adults.
110

Antibiotic-related Diarrhea

The results of many, but not all, double-blind and open trials suggest that probiotics, especially
S. boulardii
and
Lactobacillus GG
,
may help prevent or treat antibiotic-related diarrhea.
10,11,16 18,25 28,75,76,94-95, 97-98,143,183,215
For example, one study evaluated 180 people, who received either placebo or 1,000 mg of saccharomyces daily along with their antibiotic treatment, and found that the treated group developed diarrhea significantly less often.
16
A similar study of 193 people also found benefit.
18
Three additional studies involving adults found that various species of
Lactobacillus
, taken either alone in combination, to be beneficial,
174,207
even in cases of
Clostridium difficile
,
the most serious cause of antibiotic-induced diarrhea.
208

A review of 16 randomized trials further adds to this evidence.
219
This review included many different strains of probiotics (eg,
Lactobacilli
,
Lactococcus
,
Bifidobacterium
), which were used alone or in combination. Bacteria that appeared to lack evidence of benefit included
L. rhamnosus
,
L. sporogenes
,
B. lactis
, and
S. thermophilus
. Like the earlier review, the pooled results of 34 randomized trials also found evidence to support the use of probiotics for the prevention of antibiotic-associated diarrhea in both children and adults.
225

On the other hand, a study of 302 people found no benefit with
Lactobacillus GG
.
25
And, a review of four probiotic studies found insufficient evidence for their effectiveness in the treatment of
Clostridium difficile
, the most serious cause of antibiotic-induced diarrhea.
159

Although taking probiotic organisms in the proper concentration may be beneficial for antibiotic-induced diarrhea, at least one study found that consuming fresh yogurt during antibiotic treatments had no significant effect on the incidence of diarrhea.
160

Note:
Diarrhea that occurs in the context of antibiotics may be dangerous; for this reason, physician consultation is essential.

Other Forms of Diarrhea

Two double-blind, placebo-controlled studies enrolling a total of almost 700 people undergoing
radiation
therapy for cancer found that use of probiotics significantly improved radiation-induced diarrhea.
79,136
Similar evidence supports the use of
Lactobacillus rhamnosus
,
153
as well as a special, nonpathogenic form of
E. coli
.
78
However, of 85 women receiving pelvic radiation for cervical or uterine cancer, those who consumed a liquid yogurt preparation enriched with
Lactobacillus casei
had no less diarrhea than those who took a placebo drink.
161

Small double-blind studies suggest
S. boulardii
might be helpful for treating chronic diarrhea in people with HIV, hospitalized patients being tube-fed, and people with Crohn's disease.
11,19 21

Premature infants weighing less than 2,500 grams (5.5 pounds) are at risk for a life-threatening intestinal condition called necrotizing enterocolitis (NEC). In a study that pooled the results of 9 randomized, placebo-controlled trials involving 1,425 infants, probiotic supplementation significantly reduced the occurrence of NEC and death associated with it.
177
A subsequent study found similar benefits in very low birth weight infants weighing less than 1,500 grams (3.3 pounds).
189
For one probiotic strain,
L. reuteri
, there may be other benefits, as well. In another study involving 249 premature infants, those treated with
L. reuteri
experienced fewer gastrointestinal symptoms, received fewer antibiotics, and were hospitalized less frequently than those treated with
L. rhamnosus
or no probiotic.
213

Inflammatory Bowel Disease (Ulcerative Colitis and Crohn’s Disease)

The conditions
Crohn’s disease
and
ulcerative colitis
fall into the family of conditions known as inflammatory bowel disease. Chronic diarrhea is a common feature of these conditions.

A double-blind trial of 116 people with ulcerative colitis compared probiotic treatment against a relatively low dose of the standard drug mesalazine.
37
The results suggest that probiotic treatment might be equally effective as low-dose mesalazine for controlling symptoms and maintaining remission. Evidence of benefit was seen in other trials, as well.
38,82,112
For example, a 2011 review of 4 randomized trials with a total of 587 patients seemed to support the use of probiotics to reduce the relapse rates in people with ulcerative colitis.
222
The authors, though, pointed out the need for better designed trials.

One preliminary study found
S. boulardii
helpful for mild diarrhea in stable Crohn’s disease.
20
However, two studies failed to find benefit with
Lactobacillus
probiotics,
113-114
and in an analysis of 8 randomized, placebo-controlled studies, probiotics were ineffective at maintaining remission in Crohn’s disease patients.
165

Probiotics might be useful for people with ulcerative colitis who have had part or all of the colon removed. Such people frequently develop a complication called pouchitis, inflammation of part of the remaining intestine. A 9-month, double-blind trial of 40 people found that a combination of three probiotic bacteria could significantly reduce the risk of a pouchitis flare-up in people with chronic pouchitis.
39
Participants were given either placebo or a mixture of various probiotics, including four strains of
Lactobacilli
,
three strains of
Bifidobacteria
,
and one strain of
Streptococcus salivarius
.
The results showed that treated people were far less likely to have relapses of pouchitis. Another study found that probiotics used right after surgery can help prevent pouchitis from developing at all.
80
One study, however, failed to find benefit with
Lactobacillus johnsonii
in people with Crohn’s disease who have undergone a similar operation.
129

Finally, some evidence hints that probiotics might reduce the joint pain that commonly occurs in people with either kind of inflammatory bowel disease.
115

Irritable Bowel Syndrome

People with
irritable bowel syndrome (IBS)
experience crampy digestive pain as well as alternating diarrhea and constipation and other symptoms. Although the cause of irritable bowel syndrome is not known, one possibility is a disturbance in healthy intestinal bacteria. Based on this theory, probiotics have been tried as a treatment for IBS, with some success.

For example, in a 6-week double-blind, placebo-controlled trial of 274 people with constipation-predominant irritable bowel syndrome, use of a probiotic formula containing
Bifidobacterium animalis
significantly reduced discomfort and increased stool frequency.
144
In another trial of 298 IBS patients, 8 weeks of treatment with beneficial
Escherichia coli
reduced typical symptoms compared to placebo.
200
In a review of 3 randomized trials,
Lactobacillus rhamnosus GG
was associated with improvement in symptom, especially a reduction in abdominal pain, among 393 children with IBS.
223
And finally, a 4-week randomized trial involving 122 people with IBS found evidence that
B. bifidum
improved symptoms and quality of life compared to placebo.
224

Benefits have also been seen in small, double-blind trials using
L. plantarum
,
2,53,70L. acidophilus
,
3,163L. rhamnosus
,
130L. salivarus
and
Bifidobacterium
,
116,188
in addition to
proprietary probiotic combinations including various strains.
54,117,156,187
One such combination, called VSL#3, contains
B. longum
,
B. infantis
,
L. acidophilus
,
L. plantarum
,
L. casei
,
L. bulgaricus
, and
Streptococcus thermophilus
. In a double-blind,
crossover trial
, 59 children aged 5-18 years old were randomized to receive VSL#3 or placebo for 6 weeks.
214
After a 2-week "wash-out" period, the children were switched to the other treatment. VSL#3 was associated with a reduction in symptoms, including abdominal pain, bloating, and gas.
Benefits have also been seen with combination
prebiotic
/probiotic formulas
118, 182, 199
and prebiotics alone.
197

Of course, other studies have failed to find probiotics more effective than placebo.
68,119,172
One randomized trial involving 90 people with diarrhea-predominant IBS found
Saccharomyces boulardii
to be more effective than placebo at improving quality of life.
216
But, the probiotic did not seem to improve the actual symptoms of IBS.
Two studies that pooled previous randomized trials on the use of probiotics for IBS came to similar conclusions: probiotics appear to offer some benefit, most notably for global symptoms and abdominal discomfort. However, these two studies were unable to determine which probiotic species were most effective.
178,179

Eczema

Use of probiotics during pregnancy and after childbirth may reduce risk of childhood
eczema
. In a very large, long-term, double-blind study, 1,223 pregnant women were given either placebo or a probiotic mixture (containing
Lactobacilli
and
Bifidobacteria
) beginning 2-4 weeks before delivery.
125
Their newborn children then received either probiotics or placebo for six months. The results showed that the probiotics mixture markedly reduced the incidence of eczema (though not of other allergic diseases).
However, in a follow-up to this study, researchers found that the probiotic supplementation was not associated with reduced eczema in children followed through age 5. The probiotics also had no effect on allergic rhinitis or asthma.
193

Another study also yielded marginal results,
139
and a third study involving only lactobacillus found no benefit at all for the prevention of eczema. This latter study actually demonstrated a modestly increased the risk of wheezing bronchitis in infants who took the probiotic.
168
But, some probiotics combined with prebiotics may help to reduce wheezing in infants with eczema. For example,
Bifidobacterium breve
and a galacto-/fructo-oligosaccharide mixture (Immunofortis) showed benefit in one randomized study involving 90 infants.
206

Bifidobacterium longum
and
Lactobacillus rhamnosus
supplementation did not reduce incidence of eczema atopic dermatitis or allergic sensitization at 12 months among Asian infants at risk of allergic diseases.
196

Researchers in another study concluded that not all probiotics are created equal. In this placebo-controlled study involving pregnant women and their infants,
Lactobacillus rhamnosus
reduced the incidence of eczema in the children, but a strain of
Bifidobacterium animalis
did not.
186

According to some but not all studies, infants who already have eczema may benefit from probiotics.
30,51,52,77,120-121,128,154,166
However, a careful review of 12 studies involving a total of 781 children found no convincing evidence that probiotics can effectively treat eczema in this age group.
191

If probiotics are beneficial for childhood eczema, they are probably more effective at preventing the condition rather than treating it. A carefully conducted review of numerous studies cautiously concluded that probiotics may help reduce the risk of eczema in infants and children, particularly those at high risk.
154
And two subsequent reviews found that probiotics were more effective at preventing childhood eczema, particularly when given both to mother (before birth) and infant.
166,173

Immunity

A number of studies suggest that various probiotics can enhance
immune function
. One 12-week, double-blind, placebo-controlled trial evaluated 25 healthy elderly people, half of whom were given milk containing a particular strain of
Bifidobacterium lactis
,
the others milk alone.
42
The results showed various changes in immune parameters which the researchers took as possibly indicating improved immune function. Another double-blind, placebo-controlled study of 50 people using
B. lactis
had similar results.
41

A 7-month, double-blind, placebo-controlled study of 571 children in daycare centers in Finland found that use of milk fortified with
Lactobacillus GG
reduced the number and severity of respiratory infections.
43
In another controlled trial, probiotics (
Lactobacillus rhamnosus GG
and
Bifidobacterium lactis
Bb-12) given daily to infants in their formula significantly reduced the risk of acute
otitis media
and recurrent respiratory infections during the first year of life compared to placebo.
192

Benefits were seen in three other large studies, in which probiotics combined with multivitamins and minerals helped prevent colds (or reduce their duration and severity) in adults.
122-124
However, a smaller and shorter study failed to find any effect on respiratory infections.
81
Similarly,
Lactobacillus fermentum
given to 20 healthy elite distance runners over a 4-month period during winter training was significantly more effective at reducing the number and severity of respiratory symptoms compared with a placebo.
164

One study found that
Lactobacillus
GG
or
L. acidophilus
may improve the immune response to vaccinations.
83

Cholesterol

An 8-week, double-blind, placebo-controlled trial of 70 overweight people found that a probiotic treatment containing
S. thermophilus
and
Enterococcus faecium
could reduce LDL ("bad") cholesterol by about 8%.
45
Similarly positive results were seen in other short-term trials of various probiotics.
44,46,73,74,100-101
However, a 6-month, double-blind, placebo-controlled trial found no long-term benefit.
72
Researchers speculate that participants stopped using the product regularly toward the later parts of the study.

Sinusitis

The addition of the probiotic
Lactobacillus rhamnosus
to regular was no better than than placebo in 77 patients with chronic rhinosinusitis.
201

Safety Issues

Probiotics may occasionally cause a temporary increase in digestive gas. But, beyond that, they do not present any known risks for most people. In one trial of 140 healthy infants, formula supplemented with long-chain polyunsaturated fatty acids and probiotics appeared as safe as standard formula, and did not have any effect on infant growth by the end of the 7-month trial.
194

However, individuals who are immunosuppressed could conceivably be at risk for developing a dangerous infection with the probiotic organism itself; at least one person taking immunosuppressive medications has died in this manner.
31

In a detailed review of four studies, researchers concluded that the use probiotics did not benefit patients with severe acute pancreatitis.
184
Furthermore, according to one study, the use of probiotics led to an increased risk of mortality in patients with severe acute pancreatitis, and should, therefore, be avoided under these circumstances.
167

Interactions You Should Know About

If you are taking
antibiotics
: It may be beneficial to take probiotic supplements at the same time, and to continue them for a couple of weeks after you have finished the course of drug treatment. This will help restore the balance of natural bacteria in your digestive tract.

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Chicken soup for a cold? Holding your breath to halt your hiccups? Friends and family swear by these common cures. But you're not so sure. You've heard all the age-old remedies, but can you decipher fact from fiction? Find out how much you really know in this home remedy quiz.Find out how much you really know in this home remedy quiz.

193.
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Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY.
Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.